A semiconductor package component such as a BGA (Ball Grid Array) component having electrodes formed on the underside is mounted in one of the process illustrated in FIGS. 17(a) to 17(e) and the process illustrated in FIGS. 18(a) to 18(d).
In FIGS. 17(a) and 17(b), a semiconductor package component 3 is mounted on a substrate 1 in such a manner that bump electrodes 4 of the semiconductor package component 3 come into contact with electrodes 2 on the substrate 1.
In FIG. 17(c), reflow is performed. In the reflow, the solder of the bump electrodes 4 melts and the semiconductor package component 3 moves to a proper position by the self-alignment effect. Then the substrate and component are cooled to the melting temperature of the solder or lower to solidify the solder, so that electrical connection between the semiconductor package component 3 and the substrate 1 is completed.
In FIG. 17(d), a thermoset resin 5 is injected between the semiconductor package component 3 and the substrate 1 with a syringe or the like.
In FIG. 17(e), the substrate 1 is heated to a temperature not lower than the curing temperature of the thermoset resin 5 to cure the thermoset resin 5, thereby mechanically fixing the semiconductor package component 3 onto the substrate 1.
The method illustrated in FIGS. 17(a) to 17(e) involves two heating steps, the reflow in FIG. 17(c) and the heating in FIG. 17(e). In contrast, the process illustrated in FIGS. 18(a) to 18(d) involves only one heating step.
In FIGS. 18(a) and 18(b), the thermoset resin 5 is applied to a position 6 on the substrate 1 where the semiconductor package component 3 is to be mounted. FIG. 19 illustrates how the thermoset resin 5 is applied.
In FIG. 18(c), the semiconductor package component 3 is mounted on the substrate 1 in such a manner that the bump electrodes 4 of the semiconductor package component 3 come into contact with the electrode 2 on the substrate 1. At this point, the uncured thermoset resin 5 is in contact with the substrate 1 and the underside of the semiconductor package component 3.
In FIG. 18(d), reflow is performed. In the reflow, the solder of the bump electrodes 4 melts. Since the thermoset resin 5 is uncured at this point in time, the semiconductor package component 3 is moved to the proper position by the self-alignment effect of the melted solder between the electrodes on the substrate 1 and the electrodes of the semiconductor package component 3. After the thermoset resin 5 is cured by heating, the temperature decreases to a temperature not higher than the melting temperature of the solder to solidify the solder, so that the electrical connection and mechanical bonding of the semiconductor package component 3 to the substrate 1 are completed. FIG. 20 illustrates the completion of the mounting.